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Android APIs
public final class

NdefFormatable

extends Object
implements TagTechnology
java.lang.Object
   ↳ android.nfc.tech.NdefFormatable

Class Overview

Provide access to NDEF format operations on a Tag .

Acquire a NdefFormatable object using get(Tag) .

Android devices with NFC must only enumerate and implement this class for tags for which it can format to NDEF.

Unfortunately the procedures to convert unformated tags to NDEF formatted tags are not specified by NFC Forum, and are not generally well-known. So there is no mandatory set of tags for which all Android devices with NFC must support NdefFormatable .

Note: Methods that perform I/O operations require the NFC permission.

Summary

Public Methods
void close ()
Disable I/O operations to the tag from this TagTechnology object, and release resources.
void connect ()
Enable I/O operations to the tag from this TagTechnology object.
void format ( NdefMessage firstMessage)
Format a tag as NDEF, and write a NdefMessage .
void formatReadOnly ( NdefMessage firstMessage)
Formats a tag as NDEF, write a NdefMessage , and make read-only.
static NdefFormatable get ( Tag tag)
Get an instance of NdefFormatable for the given tag.
Tag getTag ()
Get the Tag object backing this TagTechnology object.
boolean isConnected ()
Helper to indicate if I/O operations should be possible.
[Expand]
Inherited Methods
From class java.lang.Object
From interface android.nfc.tech.TagTechnology
From interface java.io.Closeable
From interface java.lang.AutoCloseable

Public Methods

public void close ()

Disable I/O operations to the tag from this TagTechnology object, and release resources.

Also causes all blocked I/O operations on other thread to be canceled and return with IOException .

Requires the NFC permission.

Throws
IOException

public void connect ()

Enable I/O operations to the tag from this TagTechnology object.

May cause RF activity and may block. Must not be called from the main application thread. A blocked call will be canceled with IOException by calling close() from another thread.

Only one TagTechnology object can be connected to a Tag at a time.

Applications must call close() when I/O operations are complete.

Requires the NFC permission.

Throws
IOException

public void format ( NdefMessage firstMessage)

Format a tag as NDEF, and write a NdefMessage .

This is a multi-step process, an IOException is thrown if any one step fails.

The card is left in a read-write state after this operation.

This is an I/O operation and will block until complete. It must not be called from the main application thread. A blocked call will be canceled with IOException if close() is called from another thread.

Requires the NFC permission.

Parameters
firstMessage the NDEF message to write after formatting, can be null
Throws
TagLostException if the tag leaves the field
IOException if there is an I/O failure, or the operation is canceled
FormatException if the NDEF Message to write is malformed

public void formatReadOnly ( NdefMessage firstMessage)

Formats a tag as NDEF, write a NdefMessage , and make read-only.

This is a multi-step process, an IOException is thrown if any one step fails.

The card is left in a read-only state if this method returns successfully.

This is an I/O operation and will block until complete. It must not be called from the main application thread. A blocked call will be canceled with IOException if close() is called from another thread.

Requires the NFC permission.

Parameters
firstMessage the NDEF message to write after formatting
Throws
TagLostException if the tag leaves the field
IOException if there is an I/O failure, or the operation is canceled
FormatException if the NDEF Message to write is malformed

public static NdefFormatable get ( Tag tag)

Get an instance of NdefFormatable for the given tag.

Does not cause any RF activity and does not block.

Returns null if NdefFormatable was not enumerated in getTechList() . This indicates the tag is not NDEF formatable by this Android device.

Parameters
tag an NDEF formatable tag
Returns
  • NDEF formatable object

public Tag getTag ()

Get the Tag object backing this TagTechnology object.

Returns

public boolean isConnected ()

Helper to indicate if I/O operations should be possible.

Returns true if connect() has completed, and close() has not been called, and the Tag is not known to be out of range.

Does not cause RF activity, and does not block.

Returns
  • true if I/O operations should be possible